Research On Precision Die Forging Technology Of Universal Joint

With the development of manufacturing processes,the competition of auto parts has become more and more fierce.Both the development of new materials and the application of new parts manufacturing processes can effectively reduce the production cost of automobiles and improve the application performance of the whole vehicle.The truck is driven by the rear wheel.The drive shaft system transmits the power of the engine to the rear wheel.Therefore,the reliability and safety of the drive shaft determine the performance of the vehicle.The fork parts on the drive shaft are key joint parts in the drive shaft of the car,which have poor working environment,heavy load and high comprehensive mechanicality.These fork-shaped parts are usually formed by open die forging of high-quality alloy steel,and the material utilization rate is generally low.The weight of the forged part is more than 20% of the weight of the forging.In this paper,aiming at a certain type of universal joint fork,aiming at improving material utilization rate and cost saving,the theoretical analysis,numerical simulation and physical experiment research methods are used to analyze the forming characteristics of the existing horizontal open die forging process.The improvement is carried out,and a new die forging process scheme is proposed: local heating at the end ? flat forging roughing blank ? open pre-forging ? open final forging ? trimming.Through numerical simulation and physical experiments,the scheme is reasonable and feasible.Compared with the current open die forging process,the new process uses the blank of the same diameter as the forging part in the selection of the blank,local heating,and the volume required for the metal forming of the fork after the blanking is finished,and the rod is not realized.The flashing forging slightly reduces the weight of the flash of the fork,and the material utilization rate is increased by more than 7%.In the new process,the main forming methods of metal are upsetting and composite extrusion.Based on the idea of the new process,this paper has done the following work:(1)The geometry and metal flow law of the universal joint fork were analyzed.The steps of upsetting,pre-forging,final forging and trimming die forging were designed using Pro/E software.(2)The DEFORM-3D software is used to simulate the forging forming process,and the simulation results are analyzed to continuously optimize the process parameter,which proves the rationality of the die forging process.(3)Design and manufacture of forging dies.The blanking forging die is installed on the flat forging machine,and the pre-forging and final forging die are mounted on a 1000-ton screw press.The blank positioning structure is designed in the pre-forging die,and the purpose is to place the blank horizontally to avoid large deformation of the forging rod contact with the mold wall.(4)A process experiment was carried out.The experiment was verified by the experiment,and the scheme was reasonable and feasible.The forgings were qualified by the appearance observation and shape inspection.